The present invention relates to power tools and, more particularly, to a handle arrangement for power tools.
A power tool, such as a circular saw, generally includes a housing supporting a motor which rotatably drives a tool element, such as a saw blade. Typically, an operator""s handle is integrally formed with the housing. In a circular saw, a shoe plate supports the saw on the surface of a workpiece.
In some circular saws, the housing is adjustable relative to the shoe plate to change the depth of cut of the saw blade. For example, the housing may pivot relative to the shoe plate about an axis adjacent the front of the shoe plate (front pivot depth adjustment) or about an axis adjacent the rear of the shoe plate (rear pivot depth adjustment). In another construction, the shoe plate is slidably lowered and raised relative to the housing (drop shoe depth adjustment). In each of these depth adjustment arrangements, when the depth of cut of the saw blade is adjusted, the position and/or orientation of the handle relative to the workpiece is also adjusted.
U.S. Pat. No. 4,516,324 discloses a modular housing system for a circular saw. The circular saw includes a single, one-piece housing having an interface portion which interchangeably mounts either a pivot adjust subassembly or a vertical (drop shoe) adjust subassembly for changing the depth of cut of the circular saw. The main handle can have either a xe2x80x9cpush handlexe2x80x9d configuration or a xe2x80x9ctop handlexe2x80x9d configuration. The selected handle component is slipped onto the one-piece field case and secured by fasteners.
One of the problems with a circular saw including an operator""s handle that is integrally formed with the housing, is that, in some cutting operations, the operator may prefer a xe2x80x9cpush handlexe2x80x9d to a xe2x80x9ctop handlexe2x80x9d or vice versa. However, the operator cannot adjust the handle to the desired position relative to the housing. Another problem with a circular saw with an integral handle is that, when the depth of cut of the saw blade is adjusted, the handle position and orientation also changes. The resulting handle position is often uncomfortable and is seldom the optimal position for operation of the circular saw.
For example, in a circular saw with a front pivot depth adjustment assembly, at full depth of cut, the handle is typically positioned as a xe2x80x9cpush handlexe2x80x9d. At a minimum depth of cut, the handle position is changed to a xe2x80x9ctop handlexe2x80x9d position. In a circular saw with a rear pivot depth adjustment assembly, at full depth of cut, the handle must be oriented above a typical xe2x80x9cpush handlexe2x80x9d position because, when the saw is adjusted to a minimum depth of cut, the handle is lowered.
One problem with the handle arrangement disclosed in U.S. Pat. No. 4,516,324 is that the circular saw includes two separate handles. The handle component that is not in use must be stored and may be lost or damaged.
Another problem with the handle arrangement disclosed in U.S. Pat. No. 4,516,324 is that the saw includes a handle that is only a xe2x80x9cpush handlexe2x80x9d or a xe2x80x9ctop handlexe2x80x9d and that is not adjustable between these configurations. Additional fasteners are also required.
The present invention provides a handle arrangement for a power tool that alleviates the problems with the above-described handle arrangements. The invention provides a power tool, such as a circular saw, that includes a handle that is movable relative to the motor housing. Preferably, the handle is pivotable about the axis of the saw blade relative to the motor housing.
Also, the invention provides a locking assembly for locking the handle in a position relative to the housing. Preferably, the locking assembly provides a frictional engagement between the handle and the housing and includes a clamping member that releasably applies a clamping force to the housing to lock the handle in a position relative to the housing. Preferably, the locking assembly also provides a positive engagement between the handle and the housing and includes inter-engaging teeth formed on both the handle and the housing.
Further, the invention provides means for connecting the switch to the motor to accommodate movement of the switch with the handle and relative to the motor. Preferably, the connecting means are provided by a wiring arrangement.
In addition, the invention provides interaction between the switch and the locking assembly to prevent inadvertent operation of one when the other is operated. Specifically, the switch preferably cannot be operated when the locking assembly is unlocked, and the locking assembly cannot be unlocked when the switch is connecting the motor to the power source.
One advantage of the present invention is that the handle is movable relative to the housing of the power tool to allow the operator to position the handle as desired for a given cutting operation. As a result, the operator can adjust the handle to a position that is most comfortable and allows the greatest control of the circular saw during cutting operations.
Another advantage of the present invention is that, when the circular saw is adjusted to change the depth of cut of the saw blade, the operator can also adjust the handle to an optimum position for the given cutting operation.
Yet another advantage of the present invention is that the circular saw does not include additional components that must be substituted for one another to change the configuration of the handle or additional fasteners. This reduces the chance that such an additional component is lost or damaged and also eliminates the need to store additional components.
A further advantage of the present invention is that the handle is adjustable to substantially any position between a first position, such as a xe2x80x9cpush handlexe2x80x9d position, and a second position, such as a xe2x80x9ctop handlexe2x80x9d position.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings.